56 POISONOUS PROTEINS 



mal. When we come to speak of the autolytic 

 cleavage of unicellular organisms, such as bac- 

 teria, we have quite a different problem. That 

 bacteria undergo autolytic cleavage and that 

 the products formed in this process may be 

 harmful to multicellular organisms has been 

 abundantly shown. Old cultures of colon and 

 typhoid bacilli may contain soluble split prod- 

 ucts which are highly harmful and indeed may 

 be fatally effective in their action on the higher 

 animals. Whether pathogenic bacteria undergo 

 autolytic cleavage in the bodies of their hosts is 

 a question which, so far as I know, has not been 

 decisively determined by experiment. The pre- 

 sumption is that this may and does happen. 



The following experimental data concerning 

 the autolytic cleavage of bacterial proteins may 

 be of interest in this connection : 



Eosenow has shown that pneumococci sus- 

 pended in salt solution and kept at 37 for forty- 

 eight hours, under ether or over chloroform, 

 undergo autolysis with the liberation of a poi- 

 son. This poison injected intravenously or in- 

 tracardiacly in normal animals induces ana- 

 phylactic shock. In guinea-pigs death results 

 from bronchial spasm and consequent arrest of 

 respiration. In dogs it causes marked fall in 



